The chemicals between us-First results of the cluster analyses on anatomy embalming procedures in the German-speaking countries

Hands-on courses utilizing preserved human tissues for educational training offer an important pathway to acquire basic anatomical knowledge. Owing to the reevaluation of formaldehyde limits by the European Commission, a joint approach was chosen by the German-speaking anatomies in Europe (Germany, Austria, Switzerland) to find commonalities among embalming protocols and infrastructure. A survey comprising 537 items was circulated to all anatomies in German-speaking Europe. Clusters were established for "ethanol"-, formaldehyde-based ("FA"), and "other" embalming procedures, depending on the chemicals considered the most relevant for each protocol. The logistical framework, volumes of chemicals, and infrastructure were found to be highly diverse between the groups and protocols. Formaldehyde quantities deployed per annum were three-fold higher in the "FA" (223 L/a) compared to the "ethanol" (71.0 L/a) group, but not for "other" (97.8 L/a), though the volumes injected per body were similar. "FA" was strongly related to table-borne air ventilation and total fixative volumes ≤1000 L. "Ethanol" was strongly related to total fixative volumes >1000 L, ceiling- and floor-borne air ventilation, and explosion-proof facilities. Air ventilation was found to be installed symmetrically in the mortuary and dissection facilities. Certain predictors exist for the interplay between the embalming used in a given infrastructure and technical measures. The here-established cluster analysis may serve as decision supportive tool when considering altering embalming protocols or establishing joint protocols between institutions, following a best practice approach to cater toward best-suited tissue characteristics for educational purposes, while simultaneously addressing future demands on exposure limits.

Extended reality visualization of medical museum specimens: Online presentation of conjoined twins curated by Dr. Jacob Henle between 1844-1852

Background:

The purpose of this study is to characterize a full-term conjoined twins’ cadaver curated by Dr. Jacob Henle sometime between 1844 and 1852 and demonstrate digital distribution of an old and rare medical museum specimen using an extended reality (XR) model workflow.

Methods:

The cadaver (Preparation 296) is in the Department of Anatomy and Cell Biology at the University of Heidelberg. An XR display workflow comprises image capture, segmentation, and visualization using CT/MR scans derived from the cadaver. Online radiology presentation to medical students focuses on diagnostic characteristics of anatomical systems depicted with XR models.

Results:

Developmental defects in Preparation 296 include duplicated supradiaphragmatic structures and abnormal osteological features. Subdiaphragmatically, the gut is continuous on the right, but terminates at the distal esophagus on the left. One large liver occupies the abdomen with one spleen located on the left side. Observations suggest duplication of the primitive streak and separate notochords rostrally. Duplication occurs near the yolk sac and involves midgut formation while secondary midline fusion of the upper extremities and ribs likely results from the proximity of the embryos during development. Medical students access the model with device agnostic software during the curricular topic “Human Body Plan” that includes embryology concepts covering mechanisms of twinning.

Conclusions:

The workflow enables ease-of-access XR visualizations of an old and rare museum specimen. This study also demonstrates digital distribution and utilization of XR models applicable to embryology education.

Strengths and Weaknesses of Non-enhanced and Contrast-enhanced Cadaver Computed Tomography Scans in the Teaching of Gross Anatomy in an Integrated Curriculum

Cadaver-specific postmortem computed tomography (PMCT) has become an integral part in anatomy teaching at several universities. Recently, the feasibility of contrast-enhanced (CE)-PMCT has been demonstrated. The purpose of this study was to identify particular strengths and weaknesses of both non-enhanced and contrast-enhanced PMCT compared to conventional cadaver dissection. First, the students' perception of the learning effectiveness of the three different modalities have been assessed using a 34-item survey (five-point Likert scale) covering all anatomy course modules. Results were compared using the nonparametric Friedman Test. Second, the most frequent artifacts in cadaver CT scans, were systematically analyzed in 122 PMCT and 31 CE-PMCT data sets to quantify method-related limitations and characteristics. Perfusion quality was assessed in 57 vascular segments (38 arterial and 19 venous). The survey was answered by n = 257/320 (80.3%) students. Increased learning benefits of PMCT/ CE-PMCT compared to cadaver dissection were found in osteology (2/3 categories, P < 0.001), head and neck (2/5 categories, P < 0.01), and brain anatomy (3/3 categories, P < 0.01). Contrast-enhanced-PMCT was perceived particularly useful in learning vascular anatomy (10/10 categories, P < 0.01). Cadaver dissection received significantly higher scores compared to PMCT and CE-PMCT in all categories of the abdomen and thorax (7/7 categories, P < 0.001), as well as the majority of muscular anatomy (5/6 categories, P < 0.001). Frequent postmortem artifacts (total n = 28, native-phase n = 21, contrast injection-related n = 7) were identified and assessed. The results of this work contribute to the understanding of the value of integrating cadaver-specific PMCT in anatomy teaching.

Intraosseous vascular access through the anterior mandible--a cadaver model pilot study

Background

Several insertion sites have been described for intraosseous puncture in cases of emergencies when a conventional vascular access cannot be established. This pilot study has been designed to evaluate the feasibility of the mandibular bone for the use of an intraosseous vascular access in a cadaver model.

Methodology/Principal Findings

17 dentistry and 16 medical students participating in a voluntary course received a short introduction into the method and subsequently used the battery powered EZ-IO system with a 15 mm cannula for a puncture of the anterior mandible in 33 cadavers. The time needed to perform each procedure was evaluated. India ink was injected into the accesses and during the anatomy course cadavers were dissected to retrace the success or failure of the puncture. Dental students needed 25.5±18.9(mean±standard deviation)s and medical students 33±20.4 s for the procedure (p = 0.18). Floor of mouth extravasation occurred in both groups in 3 cases. Success rates were 82 and 75% (p = 0.93).

Conclusions/Significance

Despite floor of mouth extravasation of injected fluid into a mandibular intraosseous access might severely complicate this procedure, the anterior mandible may be helpful as an alternative to other intraosseous and intravenous insertion sites when these are not available in medical emergencies.

Anatomical Position of Four Different Transobturator Mesh Implants for Female Anterior Prolapse Repair

Purpose: Polypropylene mesh implants are frequently used for pelvic floor reconstruction in women. Yet they vary in size and fixation. The purpose of this study is to compare four mesh products with regard to their anatomical positioning and functionality within the pelvic floor, to determine whether each mesh fits equally well in a female cadaver. Methods: One female pelvis was dissected, opening the retropubic space exposing the endopelvic fascia and demonstrating the arcus tendineus fasciae pelvis (ATFP). Anatomical parameters were measured before and after implanting four meshes via the transobturator approach. Results: The anterior fixation of the ATFP was found to be 5 mm lateral to the symphysis in this cadaver. The endopelvic fascia covered 54.6 cm². The obturator nerve was located 35 mm from the white line. The distance of the proximal and lateral points of mesh fixation from the ischial spine or ATFP varied from 0 to 25 mm. The meshes varied in size and anatomical positioning. Conclusion: These observations demonstrate the necessity of developing optimally sized meshes and appropriate introducer techniques that can provide sufficient vaginal support. Surgeons, furthermore, need profound knowledge of anatomy, the patient's pelvic floor defect and the meshes available on the market.

[End of life care in intensive care units]

In intensive care units, death occurs after a medical decision of treatment limitation in a great majority of patients. In this context, taking care of the patient and his relatives is ethically, practically and emotionally complex. End of life is a well known factor of conflict, burnout and stress among medical and nursing teams in the ICU. The recommendations described in the following article are expected to clarify the roles and practices of the professionals involved in end of life procedures in the ICU.

Integrated teaching of anatomy and radiology using three-dimensional image post-processing

This article presents a new way of teaching by integrating both anatomy and radiology using three-dimensional image post-processing tools. One preclinical and one clinical module were developed for integrated teaching of anatomy and radiology. Potential benefits were assessed by anonymous evaluation among the 176 participating students. The students highly appreciated the new approach, especially the high degree of interactivity with the post-processing software and the possibility to correlate the real dissection with the virtual dissection. Students agreed that three-dimensional imaging and postprocessing improved their understanding of difficult anatomical topics and topographical relations. We consider the new approach to provide great additional benefits for participating students regarding preparation for everyday clinical practice. In particular, it imparts familiarity with imaging and image post-processing techniques and may improve anatomical understanding, radiological diagnostic skills and three-dimensional appreciation.

An overview of FDA medical device regulation as it relates to deep brain stimulation devices

The United States Food and Drug Administration (FDA) is charged with assuring the safety and effectiveness of a variety of medical products and the FDA's Center for Devices and Radiological Health is responsible for premarket and postmarket regulation of medical devices. In this paper, we review--from device classification and clinical studies to the final marketing application--FDA's premarket requirements and postmarket requirements as they relate to deep brain stimulation devices.

Recombinant hirudin for cardiopulmonary bypass anticoagulation: a randomized, prospective, and heparin-controlled pilot study

BACKGROUND

Lepirudin, a recombinant hirudin, is a direct acting thrombin inhibitor that has been used as a heparin alternative in patients with heparin-induced thrombocytopenia requiring on-pump cardiac surgery. To evaluate the efficacy, safety, and clinical utility of lepirudin as a cardiopulmonary bypass (CPB) anticoagulant, we compared lepirudin with heparin in a routine CPB setting.

METHODS

Twenty patients were randomly assigned to receive lepirudin (0.25 mg/kg b. w. bolus and 0.2 mg/kg b. w. added to the CPB priming) or heparin (400 U/kg b. w. bolus) with protamine reversal. Lepirudin and heparin anticoagulation during CPB was monitored using the ecarin clotting time or ACT, respectively and additional lepirudin (5 mg) or heparin (5000 U) boluses were administered.

RESULTS

The CPB circuit was performed in both groups without thromboembolic complications. Median blood loss during the first 36 hours was statistically higher ( P = 0.007) in the lepirudin group (1.226 +/- 316 ml) compared to the heparin group (869 +/- 189 ml). One patient of the lepirudin group developed pulmonary embolism 24 hours after surgery. This patient was tested homozygous for the FV-Leiden mutation.

CONCLUSION

Lepirudin provides effective CPB anticoagulation but induces a higher postoperative blood loss than heparin. Lepirudin should be restricted to patients undergoing CPB who cannot be exposed to heparin.

Macroscopic and microangiographic anatomy of the teres major muscle: a new free functional muscle flap?

BACKGROUND

The teres major can be seen as an additional head of the latissimus dorsi muscle for three-dimensional movement of the arm. It gained importance in pedicled muscle transfers for the treatment of plexus palsies and shoulder instability. Its supplying vessels belong to the subscapular system. According to the literature, the muscle was transferred only once as a free microvascular but nonfunctional graft.

METHODS

Eleven flaps from fresh cadavers were dissected and perfused with radiopaque media. The detailed macroscopic and microangiographic anatomy was investigated to determine its potential use as a free functional muscle flap.

RESULTS

Three different access routes are possible. The mean length of the flap was 158 mm, and the distal and proximal tendinous widths were 24 mm and 52 mm, respectively. A Taylor type 1 nerve and Mathes type 2 vessel distribution was found in all specimens. The main pedicle is situated in the middle third of the superomedial border of the flap and derives almost exclusively from the circumflex scapular artery. Radioangiograms indicate possible splitting of the muscle in the transverse and longitudinal directions. The nerve could always be isolated to a considerable length (66 mm) before reaching the posterior cord.

CONCLUSIONS

This anatomical study indicates that the teres major can be seen as a separate entity in the subscapular system and can be transferred as a free flap either alone or in combination. According to what is known from pedicled transfers, the donor-site morbidity should be low if the latissimus dorsi is left intact.

Prenatal growth of the interorbital septum in Macaca mulatta

The interorbital septum is the portion of the anterior cranial base directly contiguous with the eyes. It is considered to be a primitive trait that has evolved independently in various primate groups as a result of ocular and olfactory convergence with concomitant encephalization. This process is hypothesized to have reduced the size of the lateral nasal capsule exposing the anterior cranial base to the ocular apparatus and thus creating an interorbital septum. The purpose of this study was to determine whether differential growth trajectories occur among the chondrocranial elements corresponding to this hypothesis. Macaca mulatta embryos from the Zingeser Collection were selected for this analysis since this primate shows a well-developed interorbital septum throughout ontogeny. Embryos between 40 and 90 days of gestation were selected from the collection and coronal sections including the eye, anterior cranial base and lateral nasal capsule were subjected to video microscopy and computerized reconstruction using SURFdriver Software. Tissue volumes were computed for these tissues while chondrocytic growth attributes were measured utilizing stereological techniques. Results showed a strong correlation between the volume of the lateral nasal capsule and anterior cranial base and these two structures showed a consistent correlation with an increasing eye volume. Chondrocytic volume density and average diameter were larger in the lateral nasal capsule while shape, numerical density and average volume did not differ between the two tissues. These data suggest if differential growth does account for a reduction of the nasal capsule compared to the central cranial base stem, it does not appear to result from differential tissue size change. However, certain cellular growth activities leading to premature chondrocytic hypertrophy may be involved.

[Secondary splenic rupture after thrombolysis for acute myocardial infarction]

Secondary splenic rupture after thrombolysis for acute myocardial infarction. HISTORY AND ADMISSION FINDINGS: A 67-year-old male patient was admitted with acute chest pain and signs of an acute anterior myocardial infarction in the ECG. The usual contraindications were excluded and after a systemic lysis with rt-PA the ECG-alterations as well as the symptoms of angina resolved completely. 2 hours later the patient developed an acute abdomen with a severe circulatory shock. INVESTIGATIONS: On ultrasound and CT a massive intraabdominal bleeding was found. TREATMENT AND COURSE: Emergency laparotomy revealed a splenic rupture. Retrospectively, 6 weeks before admission, the patient had fallen from a ladder to his left side. This is a rare case of a secondary splenic rupture during thrombolysis for acute myocardial infarction. 2 weeks later the patient developed rein-farction with angiographically shown two vessel disease. After angioplasty of the ramus interventricularis anterior (RIVA) he was stable. CONCLUSIONS: Intravenous thrombolysis in case of acute myocardial infarction is the method of choice. In the past a great number of patients were excluded from thrombolysis because of an extensive interpretation of contraindications. The aim to reach an alteration in this use may not risk health of patients by insufficient history.

Body mass index, abdominal adiposity and blood pressure: consistency of their association across developing and developed countries

BACKGROUND

Obesity is increasing worldwide because developing countries are adopting Western high-fat foods and sedentary lifestyles. In parallel, in many of them, hypertension is rising more rapidly, particularly with age, than in Western countries.

OBJECTIVE

To assess the relationship between adiposity and blood pressure (BP) in a developing country with high average BP (The Seychelles, Indian Ocean, population mainly of African origin) in comparison to a developed country with low average BP (Switzerland, population mainly of Caucasian origin).

DESIGN

Cross-sectional health examination surveys based on population random samples.

SETTING

The main Seychelles island (Mahé) and two Swiss regions (Vaud-Fribourg and Ticino).

SUBJECTS

Three thousand one hundred and sixteen adults (age range 35-64) untreated for hypertension.

MEASUREMENTS

Body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), systolic and diastolic blood pressure (SBP and DBP, mean of two measures).

METHODS

Scatterplot smoothing techniques and gender-specific linear regression models.

RESULTS

On average, SBP and DBP were found to increase linearly over the whole variation range of BMI, WHR and WC. A modest, but statistically significant linear association was found between each indicator of adiposity and BP levels in separate regression models controlling for age. The regression coefficients were not significantly different between the Seychelles and the two Swiss regions, but were generally higher in women than in men. For the latter, a gain of 1.7 kg/m(2) in BMI, of 4.5 cm in WC or of 3.4% in WHR corresponded to an elevation of 1 mmHg in SBP. For women, corresponding figures were 1.25 kg/m(2), 2.5 cm and 1.8% respectively. Regression coefficients for age reflected a higher effect of this variable on both SBP and DBP in the Seychelles than in Switzerland.

CONCLUSION

These findings suggest a stable linear relation of adiposity with BP, independent of age and body fat distribution, across developed and developing countries. The more rapid increase of BP with age observed in the latter countries are likely to reflect higher genetic susceptibility and/or higher cumulative exposure to another risk factor than adiposity.

Neodymium:YAG laser coagulation prostatectomy: 3 years of experience with 227 patients

PURPOSE

For 3 years we prospectively followed a cumulative cohort of men who underwent neodymium:YAG laser coagulation prostatectomy to relieve bladder outlet obstruction to determine the safety, efficacy and durability of this procedure.

MATERIALS AND METHODS

A total of 227 men with symptomatic bladder outlet obstruction was treated with the Urolase side-firing laser fiber between October 15, 1991 and October 15, 1994. Voiding outcomes, including peak urinary flow rates, residual urine volumes and American Urological Association symptom scores, were measured with time, and immediate and long-term complications were assessed.

RESULTS

Median patient followup was 26 months (maximum 42). Significant improvement occurred in all measured voiding parameters, including 133% in peak flow rates and 61% in symptom scores 1 year postoperatively. Overall 87% of patients noticed improved quality of life as a result of surgery. Minimum postoperative followup was 6 months in all cases. Complications included prostatitis in 2.6% of patients, urethral stricture in 1.8%, bladder neck contracture in 4.4% and reoperation for residual prostate tissue in 5.3%.

CONCLUSIONS

Neodymium:YAG laser coagulation of the prostate represents an efficacious surgical intervention for symptomatic bladder outlet obstruction with minimal associated morbidity. Voiding outcomes are durable through 3 years.

Induction of the POU domain transcription factor Oct-2 during T-cell activation by cognate antigen

Oct-2 is a transcription factor that binds specifically to octamer DNA motifs in the promoters of immunoglobulin and interleukin-2 genes. All tumor cell lines from the B-cell lineage and a few from the T-cell lineage express Oct-2. To address the role of Oct-2 in the T-cell lineage, we studied the expression of Oct-2 mRNA and protein in nontransformed human and mouse T cells. Oct-2 was found in CD4+ and CD8+ T cells prepared from human peripheral blood and in mouse lymph node T cells. In a T-cell clone specific for pigeon cytochrome c in the context of I-Ek, Oct-2 was induced by antigen stimulation, with the increase in Oct-2 protein seen first at 3 h after activation and continuing for at least 24 h. Oct-2 mRNA induction during antigen-driven T-cell activation was blocked by cyclosporin A, as well as by protein synthesis inhibitors. These results suggest that Oct-2 participates in transcriptional regulation during T-cell activation. The relatively delayed kinetics of Oct-2 induction suggests that Oct-2 mediates the changes in gene expression which occur many hours or days following antigen stimulation of T lymphocytes.

Selection criteria for waste management processes in manned space missions

Management of waste produced during manned space exploration missions will be an important function of advanced life support systems. Waste materials can be thrown away or recovered for reuse. The first approach relies totally on external supplies to replace depleted resources while the second approach regenerates resources internally. The selection of appropriate waste management processes will be based upon criteria which include mission and hardware characteristics as well as overall system considerations. Mission characteristics discussed include destination, duration, crew size, operating environment, and transportation costs. Hardware characteristics include power, mass and volume requirements as well as suitability for a given task. Overall system considerations are essential to assure optimization for the entire mission rather than for an individual system. For example, a waste management system designed for a short trip to the moon will probably not be the best one for an extended mission to Mars. The purpose of this paper is to develop a methodology to identify and compare viable waste management options for selection of an appropriate waste management system.

Differentiation of PC12 cells with K-ras: comparison with nerve growth factor

The cell line PC12, derived from a rat pheochromocytoma, has served as a model for studies on the mechanism of action of nerve growth factor, as well as for the exploration of neuronal differentiation in general. When treated with nanomolar concentrations of nerve growth factor, these neoplastic chromaffin-like cells stop dividing and acquire, for all intents and purposes, the phenotype of mature sympathetic neurons. This phenotype is characterized by the extensive outgrowth of electrically excitable neurites, the ability to form functional synapses, and the acquisition of a number of biochemical markers. Treatment of PC12 cells with retroviral vectors encoding the K-ras, the N-ras, or the v-src oncogenes also produces a marked morphological differentiation very similar to that seen upon treatment with nerve growth factor. Treated cells stop dividing and develop an extensive network of neurites. It has recently been shown that PC12 cells differentiated with v-src, while resembling, morphologically, those treated with nerve growth factor, differ substantially in the biochemical characteristics normally associated with nerve growth factor-induced differentiation. Cells infected with K-ras also develop a neurite network similar to that seen after treatment with nerve growth factor. In addition, such cells develop tetanus toxin-binding sites and saxitoxin-binding sites, as do cells treated with nerve growth factor. Decreases in the binding of epidermal growth factor and in the activity of calpain also occur and these, as well, are characteristic of nerve growth factor-treated cells. But the adhesive properties of cells infected with K-ras are different than those of nerve growth factor-treated cells, and the former do not show an increase in the NILE glycoprotein. Finally, K-252a, an inhibitor of the actions of nerve growth factor on PC12 cells, has no effect on the neurite outgrowth produced by infection with K-ras. Thus, many of the key markers of nerve growth factor-induced differentiation of PC12 cells also appear upon differentiation with K-ras, but there are, nevertheless, some crucial differences in the properties of these two sets of cells.

Differentiation of PC12 cells with v-src: comparison with nerve growth factor

The PC12 rat pheochromocytoma cell line is used extensively as a model to study neuronal differentiation. These cells resemble adrenal chromaffin cells, differentiating both morphologically and biochemically when cultured in the presence of dexamethasone, but develop a sympathetic neuron-like phenotype when cultured in the presence of nerve growth factor. Expression of the protein product of the v-src oncogene in PC12 cells also induces neurite outgrowth similar to that resulting from nerve growth factor treatment (Alema et al: Nature 316:557-559, 1985). It is thus possible that c-src or a src-like tyrosine kinase participates in the signal transduction pathway by which nerve growth factor acts on PC12 cells. In this study a temperature-sensitive v-src gene has been introduced into PC12 cells. When cultures of these src-transformed cells are switched from the nonpermissive (40 degrees C) to the permissive (37 degrees C) temperature they elaborate neurites. The differentiation induced by src has been compared with that induced by nerve growth factor by determining whether src-transformed PC12 cells at 37 degrees C exhibit the same biochemical alterations as those induced in PC12 cells treated with nerve growth factor. Neurite extension at 37 degrees C in v-src-transformed cells, like NGF-induced differentiation, is accompanied by an increase in the nerve growth factor-inducible large external (NILE) protein. However, neurite extension in v-src-transformed cells is not blocked by the protein kinase inhibitor K-252a, which completely blocks NGF-induced neurite extension. Likewise, EGF receptor down-regulation and the development of saxitoxin and tetanus toxin binding sites are either much reduced or completely absent in src-differentiated compared with NGF-differentiated PC12 cells.

Determination of the membrane potential of vacuoles isolated from red-beet storage tissue : Evidence for an electrogenic ATPase

The membrane potential of isolated vacuoles of red beet (Beta vulgaris L.) was estimated using several methods. The quenching of the fluorescence of the cyanine dyes 3,3'-diethylthiodicarbocyanine iodide (DiS-C2-(5)) and 3,3'-dipropylthiodicarbocyanine iodide (DiS-C3-(5)) in vacuoles indicated a transmembrane potential difference, negative inside at low external potassium concentrations. The Δψ was found to be-55 mV with two other methods, the distribution of (204)T1(+) in the presence of valinomycin and the distribution of the lipophilic cation triphenylmethylphosphonium. Uncouplers reduced this value to-35 mV. High external potassium concentrations, comparable to cytosolic values, abolished the membrane potential almost completely. The addition of 1 mM Tris-Mg(2+)-ATP markedly hyperpolarized the membrane to-75 mV. This effect was prevented by inhibitors of the ATPase activity located in isolated vacuole membranes.

Characteristics of the sucrose uptake system of vacuoles isolated from red beet tissue. Kinetics and specifity of the sucrose uptake system

The uptake of sucrose against a concentration gradient into the dextran-impermeable [(3)H]H2O space of red beet (Beta vulgaris L.) vacuoles has been studied using silicone-layer-filtering centrifugation on both fluorometric and (14)C-measurement of sucrose. Sucrose transport into vacuoles proceeds partly by an active transport system and partly by passive permeation. The K M(20°C) for active sucrose uptake was found to be about 22 mM and the V Max(20°C) was about 174 nmol sucrose x (unit betacyanin)(-1) x h(-1). The temperature dependency of sucrose transport appears to have an activation energy of 35,0 KJ×mol(-1). Among various mono-, di-, and trisaccharides tested, raffinose acts as a competitive inhibitor of sucrose uptake.

Accumulation of sucrose in vacuoles isolated from red beet tissue

Vacuoles were isolated from red beets (Beta vulgaris L.) by slicing the tissue and separated using a discontinuous dextran gradient centrifugation. The uptake of sucrose against a concentration gradient into the dextran-impermeable [(3)H]-H2O space of these organelles was studied using silicone layer filtering centrifugation on both fluorometric and (14)C-measurement of sucrose. The rate is 24 nmol sucrose (unit betacyanin)(-1) h(-1) and appears to be stimulated by ATP to an uptake rate of 34 nmol. Control experiments with slices cut from red beet tissue and incubated with [(14)C]sucrose gave comparable results. An ATPase activity dependent on both Mg(2+) and K(+) seems to be localized at the inner surface of the tonoplast. This activity is strongly inhibited by EDAC and tartrate and there is no effect of oligomycin, whereas a slight stimulation was caused by DCCD.